Genetic test predicts your success in life, but not happiness

Next time you have a success, you’d better toast your genes as well as your supportive family, teachers and pets. Subtle variations across the genome can go a small way to predicting how likely a person is to have a prestigious job, a high income, to do better than their parents and to have a likeable personality – in short, to be successful.

Daniel Belsky at Duke University in Durham, North Carolina, has been looking at data on a group of 918 New Zealanders, now in their 40s, who have been studied since they were born. Researchers have collected reams of data on these individuals over their lives, including everything from the age at which they started to speak, walk and use a potty, to their movements, jobs, health, intelligence, self-control and personalities. “We have a rich picture of them,” says Belsky.

The research builds on a 2013 study looking at the genetic profiles of 126,000 people. It compared these with each person’s educational attainment – the highest level of education each person achieved. Instead of looking for individual “genes for education”, the researchers looked for subtle variations across the genome. They found thousands of genetic variations that individually were barely significant, but together offered a way of calculating what is called a “polygenic score” that accounted for 2 per cent of the variation in educational attainment.

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Genes for success

When Belsky and his colleagues looked at the genetic profiles of the New Zealanders, they found that those with higher polygenic scores not only had a greater education, but went on to achieve more in other ways. By the age of 38, they had more prestigious occupations, higher incomes, more assets and were better at managing their finances. The individuals’ polygenic scores could predict success even when the team accounted for their level of education.

The relationship held regardless of whether the person had come from a rich or poor family, too – those with a higher polygenic score were more likely to achieve upward social mobility, and do better than their parents. “You wouldn’t have predicted social mobility based on genetics,” says Robert Plomin at King’s College London. “I think it’s a heartening sign.”

Belsky’s team also found that successful people with higher polygenic scores were more likeable and friendly, both as children and adults. “It’s a ‘nice guys finish first’ story that I didn’t expect to find,” says Belsky. But the polygenic scores had no link to life satisfaction or health.

Tweaking the odds

The score can only account for a few percentage points in the variation between individuals – there are of course many other factors that determine a person’s life course. But if there are ways to improve the odds of success for an entire population by even a tiny amount, the overall impact could be huge, says Belsky.

For example, he found that those with a higher polygenic score learned to read when they were younger. A young reading age has been linked to better outcomes later in life. “You could argue in favour of investing in early language acquisition and reading,” says Belsky.

“It is important that people recognise and respect genetic scores,” says Plomin. “When kids don’t do well, we blame their teachers and parents, but kids vary genetically. [A low polygenic score] doesn’t mean a kid can’t learn, but we should recognise that it might take more effort.”

Tough choices

Sometimes even a tiny increase in the odds of a child’s success could be desirable. In IVF, multiple embryos are created before one is selected to be implanted in the uterus. When choosing, embryologists look for signs that the embryo is healthy. In some cases, the embryos are also genetically screened to check that they are free of major diseases. In theory, they could also take the polygenic score for each embryo, allowing parents to pick the one with the greatest genetic odds of future success.

“You could do that, although some might be appalled at the idea,” says Richard Olson at the University of Colorado in Boulder, who studies the genetic and environmental influences on reading and related skills.

Belsky isn’t in favour of embryo selection by polygenic score, either – partly because so many genes are involved, and we don’t know what all of their effects might be. “These are complex traits influenced by many sites throughout the genome,” he says. “If we select for them, we might also be selecting for other, less desirable outcomes.”
Journal reference: Psychological Science, DOI: 10.1177/0956797616643070